Hard- Surfacing, Building Fusion Welding Carbon Welding Non-Ferrous Metals Heating & Heat Treating Braze Welding Welding Cast Iron Welding Ferrous Metals Brazing & Soldering Equipment Set-Up Operation Equipment For OXY-Acet Structure of Steel Mechanical Properties of Metals Oxygen & Acetylene OXY-Acet Flame Physical Properties of Metals How Steels Are Classified Expansion & Contraction Prep For Welding OXY-Acet Welding & Cutting Safety Practices Manual Cutting Oxygen Cutting By Machine Appendices Testing & Inspecting
6
Regardless of the method used for cutting or forming the edges of the pieces to be welded, cleaning before
welding should never be overlooked. All traces of paint, grease, or loose dirt should be removed. A wire brush
usually will do the trick. If the edges have been oxygen-cut, all bits of adhering slag should be knocked off, chipped
off, or ground off. Heavy grinding to remove all traces of oxide from oxygen-cut edges is not necessary, however.
Preheating
While preheating is seldom necessary in the oxy-acetylene welding of steel, other than a light amount with the
same torch which will be used to do the welding, it is usually essential in the welding of cast iron. Steel castings
may also require preheating, not so much to avoid cracking as to limit the amount of distortion which might take
place due to uneven heating and cooling.
Fig. 12-7. Here are two ideas for hoods which can be fabricated in the shop for
use in preheating castings before welding.
Weight
Small
Hood
Brick
Top
1/8-in. Plate Insulated
with Asbestos
62 In.
30 In.
60 In.
3-in. Burner Holes
Large Hood
30
in.